1. Field of the Invention
The present invention relates to earth anchors and more particularly, but not by way of limitation, to an earth anchor having retractable anchor arms and an anchor skirt which is particularly suited to anchoring in soft earth, swamp or marsh lands.
2. History of the Prior Art
There have been many innovations in the development of earth anchors for supporting guy wires, anchoring mobile homes and the like. Many of these developments include anchors which have rectractable arms and after insertion into the anchoring hole, these arms are extended into the surrounding earth to provide the anchoring function.
However, the present art anchoring devices have not been totally successful for use in soft earth such as sand and around streams, rivers, lakes and oceans or in marsh lands.
In the construction of pipelines across swamps and the like, the pipelines have been anchored by the sinking of large concrete weights having attachment cables for connecting the pipeline thereto. This method has the obvious disadvantages of requiring large swamp barges for handling the concrete blocks, the gradual sinking of these blocks due to their weight and the costs of the blocks and the handling thereof.
One of the primary reasons for the failure of earth anchors in such applications is that in order to make the anchor arms retract into a package small enough to be inserted into a small drilled hole, the anchor arms must be rather narrow. Once these narrow anchor arms are extended into the soft earth, they simply do not have sufficient cross-sectional area to provide the necessary holding power. Admittedly, the arms may be made wider as taught in the patent to G. E. Beck, U.S. Pat. No. 1,081,654 issued Dec. 16, 1913, but it is then obvious that the arms cannot be retracted to fit a hole of a diameter less than the width of each one of these arms.
Further, in the use of retractable anchor arms, there has been a constant danger of the locking mechanism which holds the anchor arms into an extended position becoming loose and thereby allowing the arms to inadvertently retract and loose their anchoring power.